Links
[1] https://edesiderata.crl.edu/providers/privco
[2] http://www.privco.com/
[3] https://chrome.google.com/webstore/detail/privco/djpngaeogfjbijiniddohkomeiebjeek
[4] http://dx.doi.org/10.1080/08963568.2015.1042815
[5] http://dx.doi.org/10.5260/chara.14.3.44